[commit: ghc] master: Add OverloadedLists, allowing list syntax to be overloaded (3234a4a)

[Simon Peyton-Jones]

I think so.. it's described on the wiki.  Achim may be able to help too

Simon

From: Johan Tibell [mailto:johan.tibell at gmail.com]
Sent: 14 February 2013 15:40
To: ghc-devs at haskell.org
Cc: Simon Peyton-Jones; Roman Leshchinskiy
Subject: Re: [commit: ghc] master: Add OverloadedLists, allowing list syntax to be overloaded (3234a4a)

Did we end up supporting a length hint so we can efficiently create e.g. vectors that need upfront allocation of the space before writing the elements? Or is the plan to do like we for String and have literals desugar to e.g.

fromIntList# :: Int# -> Ptr Int# -> [Int]

intList# :: Ptr Int#
intList# = [1,2,3,4]#

myliteral = fromList (fromIntList# 4 intList#)

On Thu, Feb 14, 2013 at 6:56 AM, Simon Peyton Jones <simonpj at microsoft.com<mailto:simonpj at microsoft.com>> wrote:
Repository : ssh://darcs.haskell.org//srv/darcs/ghc<http://darcs.haskell.org/srv/darcs/ghc>

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/3234a4ade7204c4206831b4c1dc4a8b23624cc6b

>---------------------------------------------------------------

commit 3234a4ade7204c4206831b4c1dc4a8b23624cc6b
Author: Simon Peyton Jones <simonpj at microsoft.com<mailto:simonpj at microsoft.com>>
Date:   Thu Feb 14 13:04:14 2013 +0000

    Add OverloadedLists, allowing list syntax to be overloaded

    This work was all done by
       Achim Krause <achim.t.krause at gmail.com<mailto:achim.t.krause at gmail.com>>
       George Giorgidze <giorgidze at gmail.com<mailto:giorgidze at gmail.com>>
       Weijers Jeroen <jeroen.weijers at uni-tuebingen.de<mailto:jeroen.weijers at uni-tuebingen.de>>

    It allows list syntax, such as [a,b], [a..b] and so on, to be
    overloaded so that it works for a variety of types.

    The design is described here:
        http://hackage.haskell.org/trac/ghc/wiki/OverloadedLists

    Eg. you can use it for maps, so that
            [(1,"foo"), (4,"bar")] :: Map Int String

    The main changes
     * The ExplicitList constructor of HsExpr gets witness field
     * Ditto ArithSeq constructor
     * Ditto the ListPat constructor of HsPat

    Everything else flows from this.

 compiler/deSugar/Check.lhs        |   15 ++--
 compiler/deSugar/Coverage.lhs     |   16 +++-
 compiler/deSugar/DsArrows.lhs     |    2 +-
 compiler/deSugar/DsExpr.lhs       |   42 +++++++----
 compiler/deSugar/DsMeta.hs        |    7 +-
 compiler/deSugar/Match.lhs        |   31 ++++++--
 compiler/hsSyn/Convert.lhs        |    6 +-
 compiler/hsSyn/HsExpr.lhs         |   12 ++-
 compiler/hsSyn/HsPat.lhs          |   12 ++-
 compiler/hsSyn/HsUtils.lhs        |    6 +-
 compiler/main/DynFlags.hs         |    2 +
 compiler/parser/Parser.y.pp       |   12 ++--
 compiler/parser/RdrHsSyn.lhs      |    4 +-
 compiler/prelude/PrelNames.lhs    |   26 ++++++-
 compiler/prelude/TysWiredIn.lhs   |    2 +-
 compiler/rename/RnEnv.lhs         |   18 +++--
 compiler/rename/RnExpr.lhs        |   45 +++++++----
 compiler/rename/RnPat.lhs         |   21 ++++-
 compiler/typecheck/TcExpr.lhs     |  111 ++++++++++++++++----------
 compiler/typecheck/TcHsSyn.lhs    |   30 ++++++--
 compiler/typecheck/TcHsType.lhs   |    2 +-
 compiler/typecheck/TcPat.lhs      |   14 +++-
 compiler/typecheck/TcRnDriver.lhs |    2 +-
 compiler/typecheck/TcRnTypes.lhs  |    2 +
 compiler/utils/Outputable.lhs     |    4 +-
 docs/users_guide/flags.xml        |    7 ++
 docs/users_guide/glasgow_exts.xml |  157 +++++++++++++++++++++++++++++++++++++
 27 files changed, 469 insertions(+), 139 deletions(-)


Diff suppressed because of size. To see it, use:

    git show 3234a4ade7204c4206831b4c1dc4a8b23624cc6b

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